Why did Stereo TV broadcast take so long to appear?

[electroking]

I'm just looking at pages 724-725 of the book 'Introduction to Communication
Systems, 3rd edition.', by Stremler, which presents a brief description of the
stereo system used from 1984 to the end of analog TV with the NTSC
standard. The pilot was at 15.734 kHz (instead of 19 kHz for FM radio),
in order to accomodate the tighter bandwidth available. I guess receiver
hardware to accomodate a pilot frequency so close to the upper limit
of the audio frequency range (nominally 15 kHz) was too hard to design for
mass production until the eighties. By the way, this pilot frequency was
chosen to be equal to the horizontal sweep frequency, another trick
worked out by those funny analog engineers. Let their technical abilities
not get forgotten in this so-called digital world...